A systematic study of the control of LH release, synthesis and pool size by the pituitary in vitro will be performed. Using the technique of continuous perfusing of isolated pituitary cells the effects of the endocrine milieu of the donor rat, GnRH, estradiol (E2) and the interaction of GnRH and E2 will be investigated. The importance of cyclic GMP on the release/synthesis of LH and its dependence on calcium ions and the redox state will be studied. The mode of action of GnRH and estradiol on LH synthesis and release with particular reference to cyclic GMP, protein synthesis and messenger RNA will be investigated. Synthesis of LH will be studied using radiolabelled aminoacids and glucosamine with immunoprecipitation, to establish the contribution of newly synthesized hormone to pool size. The effects of GnRH and estradiol on LH synthesis will also be studied. A mathematical model of the control of LH synthesis/release by the anterior pituitary will be constructed to clarify the role of these mechanisms on the control of the hypothalamic-pituitary-ovarian axis.